Adhesive-coated, contamination-control mats, commonly known or referred to as tacky mats, are well-known devices or implements which have been conventionally used to remove dirt, dust, and other contaminants from the soles of shoes, from the wheels of gurneys, carts, or other transportable apparatus, or from other objects, prior to the entrance of such objects or devices into “clean room” facilities in order to in fact maintain such “clean room” facilities in their desirably clean condition. Such “clean room” facilities may comprise, for example, hospital operating rooms, emergency rooms, critical patient care areas, or the like, or alternatively, laboratory or similar facilities within which microcircuitry and other delicate or sophisticated instrumentation is manufactured or assembled. Examples of such adhesive-coated contamination-control or tacky mats are disclosed within U.S. Pat. No. 4,559,250 which issued to Paige on Dec. 17, 1985, U.S. Pat. No. 3,785,102 which issued to Amos on Jan. 15, 1974, U.S. Pat. No. 3,717,897 which issued to Amos et al. on Feb. 27, 1973, U.S. Pat. No. 3,501,797 which issued to Nappi on Mar. 24, 1970, U.S. Pat. No. 3,400,421 which issued to Nappi et al. on Sep. 10, 1968, U.S. Pat. No. 3,083,393 which issued to Nappi on Apr. 2, 1963, and United Kingdom Patent Specification 1,340,636 which was published on Dec. 12, 1973 in the name of Nappi.
Conventional or PRIOR ART adhesive-coated, contamination-control mats have conventionally comprised two basic constructions. The first embodiment or type of adhesive-coated, contamination-control mat essentially comprises a relatively thick, single member or single layer mat fabricated, for example, from polyvinyl chloride (PVC), whereas the second embodiment or type of adhesive-coated, contamination-control mat essentially comprises a multi-layer laminated stack of adhesive-coated plastic film sheets. More particularly, as a result of the fabrication of the first embodiment or type of adhesive-coated, contamination-control mat as a relatively thick, single member or single layer mat, the weight and inertial mass of the mat enables the same to be simply disposed upon the underlying floor support structure without the need for adhesively bonding, for example, the undersurface portion of the mat to the underlying floor support structure. In addition, while the upper surface portion of the single member or single layer adhesive-coated, contamination-control mat is characterized by means of an adhesive layer which exhibits a relatively low-level of adhesiveness or tackiness so as to effectively remove dirt or dust either from the shoes of facility personnel, or from the wheels of gurneys, carts, or other transportable apparatus, while obviously not impeding the traversal of the same by facility personnel, or the movement thereacross of the transportable apparatus, it has been noted that when the upper surface portion of the single member or single layer adhesive-coated, contamination-control mat becomes soiled as a result of the accumulation of dirt and dust thereon, its effectiveness rapidly deteriorates.
Accordingly, such upper surface portion of the single member or single layer adhesive-coated, contamination-control mat must then be subjected to a water washing process or procedure, and appropriately dried so as to once again be capable of being used for its intended purposes. In addition to such cleaning process or procedure being time-consuming, the upper, adhesive-coated surface portion of the single member or single layer adhesive-coated, contamination-control mat tends to become eroded or worn as a result of being subjected to the repetitive cleaning processes or procedures. Still further, it is noted that the single member or single layer adhesive-coated, contamination control mat must either be replaced with another single member or single layer adhesive-coated, contamination-control mat, while the original single member or single layer adhesive-coated, contamination control mat undergoes its refurbishing or cleaning process or procedure, so as to permit the “clean-room” facility to be used continuously, or else the “clean-room” facility must be temporarily closed until the original single member or single layer adhesive-coated, contamination-control mat can again be used. Still further, since this particular adhesive-coated, contamination-control mat is characterized by means of a single member or single layer structure which has a relatively large thickness dimension, this embodiment or type of contamination-control mat often presents a trip hazard to facility personnel, or an obstacle over which the transportable apparatus must be forcefully moved. This embodiment or type of contamination-control mat has therefore not proven to be particularly desirable or viable.
The second embodiment or type of adhesive-coated, contamination-control mat assembly is disclosed within FIGS. 1 and 2, is generally indicated by the reference character 10, and is seen to comprise a multi-layer, laminated stack of adhesive-coated plastic film sheets 12, such as, for example, approximately thirty or sixty adhesive-coated plastic film sheets, which are disposed upon an underlying frame or substrate member 14. The adhesive-coated surface 16 of each one of the plastic film sheets 12 faces upwardly, and accordingly, when the external, upwardly disposed surface of the uppermost one of the plurality of adhesive-coated plastic film sheets 12 becomes soiled, such as, for example, when dirt and dust, as exemplified by means of the footprints 18, accumulate thereon to such a degree that the dirt and dust removal properties of such uppermost one of the plurality of adhesive-coated plastic film sheets 12 is no longer adequately effective, then such uppermost one of the plurality of adhesive-coated plastic film sheets 12 is simply removed from the laminated stack of adhesive-coated plastic film sheets so as to effectively uncover the next one of the plurality of adhesive-coated plastic film sheets 12 which is obviously clean and therefore ready for immediate use. Since this embodiment or type of adhesive-coated, contamination-control mat assembly 10 obviously does not require any washing or cleaning, the operational drawbacks or disadvantages, characteristic of the first embodiment or type of adhesive-coated, contamination-control mat, are effectively overcome or eliminated.
It is noted, however, that, in view of the fact that the uppermost ones of the adhesive-coated plastic film sheets 12 are being continually removed from the laminated stack of adhesive-coated plastic film sheets, when it is so required in order to maintain the adhesive properties of the adhesive-coated, contamination-control mat assembly 10 effective, the entire contamination-control mat assembly 10 need not be normally removed from the underlying floor support structure for cleaning and washing purposes, and therefore, it is desired to maintain the contamination-control mat assembly 10 at a fixed position with respect to the entrance-way into the “clean room” facility, other than when the supply of the adhesive-coated plastic film sheets 12 is exhausted, thereby necessitating the replacement of the entire contamination-control mat assembly 10 with a new contamination-control mat assembly. Therefore, suitable means must be provided upon the undersurface portion of the contamination-control mat assembly 10 so as to in fact maintain the contamination-control mat assembly 10 at its designated position with respect to the entranceway into the “clean room” facility. Accordingly, one means for ensuring the fact that the disposition of the contamination-control mat assembly 10 is in fact properly maintained upon the underlying floor support structure at the entranceway to the “clean room” facility resides in providing the undersurface portion of the substrate or frame member 14 of the contamination-control mat assembly 10 with suitable backing structure which has anti-slip properties.
More particularly, as may best be appreciated from FIG. 2, the substrate or frame member 14, which may be fabricated from a suitable polystyrene material, has an upper surface portion 20 of an anchor film 22, which may be fabricated from polyethylene, adhesively bonded to the undersurface portion 24 of the substrate or frame member 14 while a rubberized rug-lock fabric material 26 is suitably adhesively bonded to the undersurface portion of the anchor film 22. While this contamination-control mat assembly 10 is obviously satisfactory from an operational point of view in that the same adequately achieves its objectives of removing dirt, dust, and other contaminants from the soles of shoes, from the wheels of gurneys, carts, or other transportable apparatus, or from other objects, prior to the entrance of such objects or devices into “clean room” facilities in order to in fact maintain such “clean room” facilities in their desirably clean condition, the multiple-step fabrication process comprising, for example, the extrusion of the polystyrene substrate or frame member 14, the application of the anchor film 22 to the undersurface portion 24 of the polystyrene substrate or frame member 14, and the application of the rubberized rug-lock fabric material 26 to the undersurface portion of the anchor film 22 is time-consuming and costly to implement. In addition, there is the possibility that the anchor film 22 can partially or completely detach from the undersurface portion 24 of the polystyrene substrate or frame member 14, or alternatively, that the rubberized rug-lock fabric material 26 can partially or completely detach from the anchor film 22, either one of such scenarios presenting a hazardous condition within the particular environment.
A need therefore exists in the art for a new and improved contamination-control mat assembly which comprises a plurality of adhesive-coated sheets disposed upon a substrate or frame member, and wherein an anti-slip backing member is fabricated with the substrate or frame member by means of a one-step process such that the substrate and anti-slip backing member are integrally affixed together so as to form a composite polystyrene substrate or frame member and acrylic-rubber anti-slip backing member assembly.